University of Wollongong
Research Online
Centre for Statistical & Survey Methodology
Working Paper Series
Faculty of Engineering and Information Sciences
2012
Can telephone surveys for the whole population
provide reliable information on the health of
Aboriginal and Torres Strait Islander Australians?
Margo Barr
University of Wollongong, mlb593@uowmail.edu.au
Anthony Dillon
University of Wollongong
Mazen Kassis
Centre for Epidemiology and Evidence, North Sydney
David G. Steel
University of Wollongong, dsteel@uow.edu.au
Recommended Citation
Barr, Margo; Dillon, Anthony; Kassis, Mazen; and Steel, David G., Can telephone surveys for the whole population provide reliable
information on the health of Aboriginal and Torres Strait Islander Australians?, Centre for Statistical and Survey Methodology,
University of Wollongong, Working Paper 9-12, 2012, 14.
http://ro.uow.edu.au/cssmwp/96
Research Online is the open access institutional repository for the University of Wollongong. For further information contact the UOW Library:
research-pubs@uow.edu.au
Centre for Statistical and Survey Methodology
The University of Wollongong
Working Paper
09-12
Can telephone surveys for the whole population provide reliable
information on the health of Aboriginal and Torres Strait Islander
Australians?
Margo L Barr, Anthony Dillon, Mazen Kassis and David G Steel
Copyright © 2008 by the Centre for Statistical & Survey Methodology, UOW. Work in progress,
no part of this paper may be reproduced without permission from the Centre.
Centre for Statistical & Survey Methodology, University of Wollongong, Wollongong NSW
2522. Phone +61 2 4221 5435, Fax +61 2 4221 4845. Email: anica@uow.edu.au
Can telephone surveys for the whole population
provide reliable information on the health of
Aboriginal and Torres Strait Islander Australians?
Margo L Barr1,2, Anthony Dillon 3, Mazen Kassis1formally, David G Steel2
1
Centre for Epidemiology and Evidence, NSW Ministry of Health, 73 Miller Street, North Sydney, NSW Australia
Yooroang Garang Indigenous Student Support Unit, Faculty of Health Sciences, The University of Sydney, PO
Box 170, Lidcombe, NSW, Australia
3
Centre for Statistical and Survey Methodology, University of Wollongong, Wollongong, Australia
2
ABSTRACT
Objective
To compare prevalence estimates for Aboriginal and Torres Strait Islander Australians collected
through a telephone survey for the general population with those collected through a face-to-face
survey for Aboriginal and Torres Strait Islander Australians.
Design, setting and participants
Information about Aboriginal and Torres Strait Islander Australians from the NSW Population Health
Survey 2002-2005 and the NSW component of the 2004-05 National Aboriginal and Torres Strait
Islander Health Survey— including sample frame, study design, participant selection, final sample,
collection period, collection method, collection agency, weighting procedure, and questionnaires—were
obtained and compared. Questions that were the same, or could provide the same information, were
selected. Prevalence estimates and standard errors were calculated and compared.
Results
The sampling methods and data collection differed between the two surveys, although both had known
probabilities of selection, and both were weighted to the corresponding Aboriginal and Torres Strait
Islander population for NSW as at 31 December 2004.
The differences between prevalence estimates ranged from less than 1% for current asthma; 1-2% for
recommended vegetable consumption, influenza vaccination, pneumococcal vaccination, positive selfrated health, diabetes or high blood glucose, and overweight or obesity, just over 3% for recommended
fruit consumption; and around 8% for non-drinkers and current smoking. Only non-drinkers (27.1%
versus 19.4%; p=0.01) and current smoking (44.6% versus 52.9%; p=0.02) were statistically
significantly different.
Conclusion
Prevalence estimates for Aboriginal and Torres Strait Islander Australians, collected through telephone
health surveys for the general population, appear to be consistent with those collected through face-toface surveys specifically for Aboriginal and Torres Strait Islander Australians.
BACKGROUND
While Australians in general are among the healthiest populations, with access to a world-class health
system, this is not the case for Aboriginal and Torres Strait Islander Australians, who have a life
expectancy below that of the general Australian population (11.5 fewer years for males and 9.7 fewer
years for females).[1] Also, Aboriginal and Torres Strait Islander Australians are significantly more likely
to experience ill health and disability—and reduced quality of life because of ill health—than other
Australians.[2]
Although addressing the poorer health of Aboriginal and Torres Strait Islander Australians is a national
priority, it cannot be assumed that good intentions and targeted resources automatically result in
improved outcomes. Good quality data on the health of Aboriginal and Torres Strait Islander Australians
are needed to evaluate programs and interventions, to assess the effectiveness of policies aimed at
improving service delivery and health status, and to inform policy and program development.[3]
The poorer health of Aboriginal and Torres Strait Islander people is of concern. Given that they
comprise less than 3% of the population, changes in health status—whether positive or negative—
could happen quickly. Therefore, the regular collection of data is needed so that change is quickly
detected and acted upon. The desire for increased frequency of data collection that results in good
quality data needs to be weighed against the available resources to collect these data, and the burden
placed upon Aboriginal and Torres Strait Islander Australians in the process of collecting them.
Regularly-reported health information, such as disease morbidity and mortality, is generally available
through administrative data collections, such as emergency department presentations and hospital
admissions, and from death records. However, for Aboriginal and Torres Strait Islander Australians, the
quality of these data varies because of under-identification and under-recording of Aboriginal and
Torres Strait Islander status in these collections. Also, these administrative collections do not collect
important health data such as risk behaviours associated with both chronic and communicable
diseases, nor do they necessarily provide health status or disease estimates for the population.
Specific health and health-related surveys, such as the National Aboriginal and Torres Strait Islander
Health Survey (NATSIHS), and the National Aboriginal and Torres Strait Islander Social Survey
(NATSISS), conducted by the Australian Bureau of Statistics, are undertaken periodically,[4,5] the
latest available data being the 2004-05 NATSIHS and the 2008 NATSISS.
State based health surveys for the general population, such as the NSW Population Health Survey, SA
Monitoring and Surveillance System, Victorian Population Health Survey, WA Health and Wellbeing
Surveillance System, Queensland Health Omnibus Survey, and ACT General Health Survey,[6-11] are
not specifically designed to provide estimates on the health of Aboriginal and Torres Strait Islander
Australians. However, as they collect Aboriginal and Torres Strait Islander status from respondents,
they are a potential source of information about the health of Aboriginal and Torres Strait Islander
Australians.
The NSW Health Survey Program has produced two reports on the health of Aboriginal and Torres
Strait Islander adults from the NSW Population Health Survey. The first was based on 930 respondents
interviewed between 2002 and 2005, the second was based on 780 respondents interviewed between
2006 and 2009.[12,13]
How accurate are the estimates for Aboriginal and Torres Strait Islander Australians from a survey that
was not designed for this purpose? To investigate this question, the results for Aboriginal and Torres
Strait Islander adults from the NSW Population Health Survey 2002-2005 (NSWPHS) were compared
with NSW results from the adult component of the 2004-05 National Aboriginal and Torres Strait
Islander Health Survey (NSW-NATSIHS). Results from the NATSISS were not used, as this survey only
contains a limited number of health indicators.
METHOD
Data sources
Information about the NSWPHS and the NSW-NATSIHS for sample frame, study design, participant
selection, final sample, collection period, collection method, collection agency and weighting procedure
was obtained.
The samples from each survey were weighted to the ABS mid-year estimates as at 31 December 2004
for the Aboriginal and Torres Strait Islander population of NSW for age, sex, and geographical location,
and compared with the 2001 Census estimates for the Aboriginal and Torres Strait Islander population
of NSW.[14]
The NSWPHS and the NSW-NATSIHS questionnaires were compared and questions that were either
the same, or could potentially provide the same information, were selected for this study. These
questions included alcohol non-drinkers, fruit consumption, vegetable consumption, current smoking,
influenza vaccination, pneumococcal vaccination, self-rated health, current asthma, diabetes or high
blood glucose, and overweight or obesity. All questions were converted to indicators for the analysis
according to the definitions in Table 1.
[TABLE 1 NEAR HERE.]
Statistical methods
Unit record data for the NSWPHS were obtained from the NSW Ministry of Health,[15] and prevalence
estimates and standard errors were calculated for each indicator, taking into consideration the complex
design of this survey. A data request for the NSW-NATSIHS indicators was made of the ABS, Northern
Territory Office, which provided prevalence estimates and standard errors for these indicators.
The prevalence estimates calculated from the two independent surveys were then compared as
follows. First, the differences between each survey’s prevalence estimates were compared (d=E1−E2).
The standard error for the difference (SE(d)=√[SE(E1)2 + SE(E2)2]) and the ratio z=d/SE(d) were then
calculated to test the null hypothesis that in the population the difference d is zero. The value of z was
then compared with the standard normal distribution.[16]
RESULTS
Comparison of the survey methods
Information about the NSWPHS and the NSW-NATSIHS are summarised in Table 2. As expected,
because the NSW-NATSIHS was a specific Aboriginal and Torres Strait Islander survey, the sample
frame and design was quite different from the NSWPHS; however, the probability of selection for each
participant was available from both surveys. Both surveys were self-reported but the modes of
collection were different: telephone for the NSWPHS; face-to-face for the NSW-NATSIHS.
[TABLE 2 NEAR HERE.]
Comparison of the survey samples
The sample sizes for NSW for each survey were surprisingly similar, 930 for NSWPHS and 936 for
NSW-NATSIHS. Data from the NSW-NATSIHS were collected from August 2004 to July 2005; data for
the NSWPHS were collected from Jan 2002 to December 2005. For both surveys, the sample was
weighted to the corresponding Aboriginal and Torres Strait Islander population of NSW by age, sex,
and geography, as at 31 December 2004, excluding those living in non-private dwellings.
Representativeness of the survey samples
Although the Aboriginal and Torres Strait Islander sample for the NSWPHS contained a higher
proportion of older adults, females, and rural adults than the Census (Table 3), once the sample was
weighted by age, sex, and health area, it was representative of the Aboriginal and Torres Strait Islander
population of NSW by age and sex. For those demographic variables for which the sample was not
weighted, there was a higher percentage with an income of less than $20,000 per annum and lower
percentage with an income greater than $80,000, compared with the Aboriginal and Torres Strait
Islander population of NSW in the Census.
Although the Aboriginal and Torres Strait Islander sample for the NSW-NATSIHS contained a higher
proportion of females than the Census (Table 3), once the sample was weighted by sex, age group and
remoteness it was representative of the Aboriginal and Torres Strait Islander population by age and
sex. For those demographic variables for which the sample was not weighted, there was a higher
percentage with an income of less than $20,000 per annum, and a higher percentage paying rent,
compared with the Aboriginal and Torres Strait Islander population of NSW in the Census. It was not
possible compare urban and rural areas between surveys due to different definitions (Table 2).
The NSW-NATSIHS had a response rate of approximately 83% of in-scope households. The
participation rates for the NSWPHS over the years 2002-2005 averaged 64%. Because NSWPHS is a
health survey of the general population, it is not possible to calculate participation rates for Aboriginal
and Torres Strait Islander people only.
[TABLE 3 NEAR HERE.]
Comparison of indicators between the surveys
Figure 1 shows the prevalence estimates for the selected indicators for both surveys. The differences
between the surveys range from less than 1% for current asthma; 1-2% for recommended vegetable
consumption, influenza vaccination, pneumococcal vaccination, positive self-rated health, diabetes or
high blood glucose, and overweight or obesity; just over 3% for recommended fruit consumption; and
around 8% for alcohol non-drinkers and current smoking (Table 3). Only two of the 11 indicators were
found to be statistically significantly different between the surveys: alcohol non-drinkers (27.1% for
NSWPHS versus 19.4% for NSW-NATSIHS; p=0.01) and current smoking (44.6% for NSWPHS versus
52.9% for NSW-NATSIHS; p=0.02) (Table 3).
[FIGURE 1 NEAR HERE.]
DISCUSSION
We compared the findings of two surveys which contained information on Aboriginal and Torres Strait
Islander Australians: a general population health survey using the telephone and a face-to-face survey
that specifically targeted Aboriginal and Torres Strait Islander Australians.
We found that, although the sampling and data collection methods differed between the two surveys,
only two of the 11 indicators selected were significantly different between the surveys. These were
alcohol non-drinkers and current smoking.
Many of the indicators had large relative standard errors (RSE), particularly influenza and
pneumococcal vaccination, both of which are based on a subset of the population (50 years and over);
however, the differences between the prevalence estimates were small, so the surveys are giving
similar estimates.
Regarding the issue of adequate sample size, based on an Aboriginal and Torres Strait Islander
population of about 150,000 in NSW,[14] it is estimated that, using simple random sampling, a sample
of 400 Aboriginal and Torres Strait Islander Australians would detect differences of + 5 per cent
between prevalence estimates for the two surveys. As both surveys have complex designs—with an
average design effect of 2.1 for the NSWPHS and 2.7 for the NSW-NATSIHS—a sample size of 800
Aboriginal and Torres Strait Islander Australians is required for the NSWPHS and 1080 is required for
the NSW-NATSIHS.
Telephone surveys are a well-accepted survey method in the general population, because of a high
telephone ownership currently estimated to be over 95 per cent; however, telephone surveys have not
been used specifically for Aboriginal and Torres Strait Islander surveys. Among the Aboriginal and
Torres Strait Islander population, approximately 82 per cent of households in non-remote areas, and 43
per cent of households in remote areas, have a working telephone at home. Therefore this survey
mode would be reasonable, particularly in non-remote areas.[4,5]
It is not envisaged that the use of general population health surveys to report the health of Aboriginal
and Torres Strait Islander Australians could replace surveys specifically designed for Aboriginal and
Torres Strait Islander Australians; rather, general surveys would be used to supplement specific
surveys, providing more timely information without an additional burden on the population.
While this is a worthwhile aim, there are two aspects that need to be considered. First, as previously
described, it is well known that under-identification of Aboriginal and Torres Strait Islander status is a
significant issue in administrative data collections. The Australian Bureau of Statistics (ABS) has made
considerable investments in raising awareness among Aboriginal and Torres Strait Islander
communities about the importance of individuals correctly identifying their status. The increase in the
number of people identifying as Aboriginal and Torres Strait Islander between recent census periods
suggests that these investments have been effective.
It is possible that Aboriginal and Torres Strait Islander Australians may be more likely to identify in a
specific face-to-face survey for them, than they would in a telephone survey for the general population.
However, the NSW Population Health Survey has always had approximately 3% of respondents
identifying as Aboriginal or Torres Strait Islander, which is consistent with their proportion of the
population as measured by the Census.[14]
CONCLUSION
Prevalence estimates for Aboriginal and Torres Strait Islander Australians collected through telephone
health surveys for the general population appear to be consistent with those collected through face-toface surveys specifically for Aboriginal and Torres Strait Islander Australians. While general population
health surveys are not meant to replace surveys specifically for Aboriginal and Torres Strait Islander
Australians, they have value as a supplement to specific surveys and provide timely and needed
information.
COMPETING INTERESTS
Margo Barr is currently enrolled in a PhD at the University of Wollongong.
ACKNOWLEDGEMENTS
We acknowledge the National Centre for Aboriginal & Torres Strait Islander Statistics (NCATSIS) NT
Office, Australian Bureau of Statistics, for calculating the prevalence estimates and providing
methodological advice; Michael Giffin, Reporting and Information Manager, NSW Ministry of Health, for
editing the earlier drafts of the article.
REFERENCES
1. Experimental Life Tables for Aboriginal and Torres Strait Islander Australians, 2005–2007.
Available online at www.abs.gov.au (accessed 21 November 2011).
2. Australian Institute of Health and Welfare. Australian hospital statistics 2009–10. Canberra:
AIHW, 2011. Available online at www.aihw.gov.au (accessed 21 November 2011).
3.
Australian Institute of Health and Welfare. National Advisory Group on Aboriginal and Torres
Strait Islander Health Information and Data: Strategic Plan 2006–2008. Canberra: AIHW, 2006.
Available online at www.aihw.gov.au (accessed 21 November 2011).
4. Australian Bureau of Statistics. National Aboriginal and Torres Strait Islander Health Survey,
2004. Canberra: Australian Bureau of Statistics, 2005. Available online at www.abs.gov.au
(accessed 21 November 2011).
5. Australian Bureau of Statistics. National Aboriginal and Torres Strait Islander Social Survey,
2002. Canberra: Australian Bureau of Statistics, 2003. Available online at www.abs.gov.au
(accessed 21 November 2011).
6.
Barr M, Baker D, Gorringe M, and Fritsche L. NSW Population Health Survey: Description of
Methods. Sydney: Centre for Epidemiology and Research, NSW Department of Health. 2008.
www.health.nsw.gov.au/resources/publichealth/surveys/health_survey_method.asp (accessed
21 November 2011).
7. SA Monitoring and Surveillance System at http://health.adelaide.edu.au/pros/data/samss
(accessed 21 November 2011).
8. Victorian Population Health Survey at www.health.vic.gov.au (accessed 21 November 2011).
9. WA Health and Wellbeing Surveillance System at www.health.wa.gov.au (accessed 21
November 2011).
10. Queensland Health Omnibus Survey at www.health.qld.gov.au (accessed 21 November 2011).
11. ACT General Health Survey at www.health.act.gov.au (accessed 21 November 2011).
12. Centre for Epidemiology and Research. 2002–2005 Report on Adult Aboriginal Health from the
NSW Population Health Survey. Sydney: NSW Department of Health, 2006. Available online at
www.health.nsw.gov.au/publichealth/surveys/hsa/0205ab.asp (accessed 21 November 2011).
13. Centre for Epidemiology and Research. 2006–2009 Report on Adult Aboriginal Health from the
NSW Population Health Survey. Sydney: NSW Department of Health, 2010. Available online at
www.health.nsw.gov.au/publichealth/surveys/hsa/0609ab.asp (accessed 21 November 2011).
14. Australian Bureau of Statistics. Population Characteristics, Aboriginal and Torres Strait Islander
Australians, 2001. Canberra: Australian Bureau of Statistics, 2003. Available online at
www.abs.gov.au (accessed 21 November 2011).
15. NSW Population Health Survey 2002-2005 (HOIST). Centre for Epidemiology and Research,
NSW Ministry of Health.
16. Altman DG and Bland JM. Interaction revisited: the difference between two estimates. BMJ
2003; 326: 219. Available online at www.bmj.com/content/326/7382/219.full (accessed 21
November 2011).
Table 1 - Comparable questions and indicators, 2002–2005 NSW Population Health Survey and 2004-05
National Aboriginal and Torres Strait Islander Health Survey
Indicator
2002–2005 NSWPHS
2004-05 NSW-NATSIHS
Alcohol (non-drinkers):
Indicator includes those who are
non-drinkers
How often do you usually drink
alcohol?
1. ______ number of days
2. Less than once per week
3. I don't drink alcohol
Recommended fruit
consumption:
Indicator includes those who met
the recommended fruit
consumption of 2 serves a day.
Recommended vegetable
consumption:
Indicator includes those who met
the recommended vegetable
consumption of 5 serves a day.
Current smoking:
Indicator includes those who
smoked daily or occasionally.
How many serves of fruit do you
usually eat each day?
How long ago did you last have an
alcoholic drink?
1. 1 week or less
2. More than 1 to less than 2 weeks
3. 2 weeks to less than 1 month
4. 1 to less than 3 months
5. 3 to less than 12 months
6. 12 months or more
7. Never
8. Don’t remember
How many serves of fruit do you
usually eat each day?
How many serves of vegetables do
you usually eat each day?
How many serves of vegetables do
you usually eat each day?
Which of the following best describes
your smoking status? This includes
cigarettes, cigars and pipes.
1. I smoke daily
2. I smoke occasionally
3. I don't smoke now, but I used to
4. I've tried it a few times but never
smoked regularly
5. I've never smoked
Were you vaccinated or immunised
against flu in the last 12 months?
Do you currently smoke?
When were you last vaccinated or
immunised against pneumonia?
Did you have the pneumococcus
(pneumonia) or pneumovax injection
in the last 5 years?
Overall, how would you rate your
health during the past 4 weeks?
1. Excellent
2. Very good
3. Good
4. Fair
5. Poor
6. Very poor
Have you ever been told by a doctor
or hospital you have asthma?
In general would say that your health
is excellent, very good, good, fair or
poor?
1 Excellent
2 Very good
3 Good
4 Fair
5 Poor
Have you ever been told by a doctor
or nurse you have asthma?
Have you had symptoms of or
treatment for asthma in the last 12
months?
Have you ever been told by a doctor
or hospital you have diabetes?
Do you still get asthma?
Have you ever been told by a doctor
or hospital you have high blood
Have you ever been told by a doctor
or nurse that you have high sugar
Influenza vaccination:
Indicator includes those who
were vaccinated or immunised
against influenza in the last 12
months.
Pneumococcal vaccination:
Indicator includes those who
have been immunised against
pneumococcal disease in the last
5 years.
Self-rated health:
Indicator includes those
responding excellent, very good,
or good to a global self-rated
health status question.
Current asthma:
Indicator includes those who had
symptoms of asthma or
treatment for asthma in the last
12 months.
Diabetes or high blood
glucose:
Indicator includes those who
either had diabetes or high blood
glucose but did not have
Do you smoke regularly, that is, at
least once a day?
Do you smoke at least once a week?
Did you have the flu shot in the last
12 months?
Have you ever been told by a doctor
or nurse you have Diabetes?
gestational diabetes.
glucose?
Overweight or obesity:
Indicator includes those with a
Body Mass Index (BMI) of 25 or
higher.
How tall are you without shoes?
1. ________ centimetres
2. ________ feet ________ inches
levels in
your blood or urine?
How tall are you without shoes?
1 Centimetres
2 Feet/inches
How much do you weigh without
clothes or shoes?
1. ________ kilograms
2. ________ stones ________ lbs
How much do you weigh?
1 Kilograms
2 Stones/pounds
3 Pounds
BMI is calculated as follows: BMI
= weight(kg)/height²(m).
Table 2 - Comparison of survey methods, 2002–2005 NSW Population Health Survey and 2004-05 National
Aboriginal and Torres Strait Islander Health Survey
Survey
method
Collection
agency
Collection
period
Ethics
approval
Sample
frame
Sample
design
Design
effect
Participant
selection
2002–2005 NSWPHS
2004-05 NSW-NATSIHS
NSW Ministry of Health
Australian Bureau of Statistics
February 2002 and December 2005
August 2004 to July 2005
NSW Population and Health Services
Research Ethics Committee
The sampling frame is developed as
follows. Records from the Australia on Disk
electronic white pages (phone book) are
geo-coded using MapInfo mapping
software. The geocoded telephone
numbers are assigned to statistical local
areas and area health services. The
proportion of numbers for each telephone
prefix is calculated by health area. All
prefixes are expanded with suffixes ranging
from 0000 to 9999. The resulting list is then
matched back to the electronic white
pages. All numbers that match numbers in
the electronic white pages are flagged and
the number is assigned to the relevant geocoded area health service. Unlisted
numbers are assigned to the area health
service containing the greatest proportion
of numbers with that prefix. Numbers are
then filtered to eliminate contiguous
unused blocks of greater than 10 numbers.
The remaining numbers are then checked
against the business numbers in the
electronic white pages to eliminate
business numbers. Finally, numbers are
randomly sorted.
Stratified by health administration area.
Average 2.1 (excluding pneumococcal and
influenza)
One person from the household was
randomly selected for inclusion in the
survey.
The community sample was obtained from a random
selection of discrete Aboriginal and Torres Strait
Islander communities and outstations across
Australia from a specially developed Aboriginal and
Torres Strait Islander Community Frame (ICF). The
ICF was constructed using both 2001 Census counts
and information collected in the 2001 Community
Housing and Infrastructure Needs Survey (CHINS).
[There was actually no community sample in NSW –
community samples were only selected in WA, NT,
QLD and SA. In NSW, an area-based form of
Census Collectors Districts was used.]
Within selected communities and outstations a
random selection of dwellings was made. [as
mentioned above, this is not applicable to NSW]
Dwellings in non-community areas were selected
using a stratified multistage area sample. A sample
of Census Collection Districts (CDs) was randomly
selected with the likelihood of a CD's selection based
on the number of dwellings containing Aboriginal and
Torres Strait Islander persons in the area as at the
2001 Census of Population and Housing. A random
selection of dwellings within selected CDs were then
screened to assess their usual residents' Aboriginal
and Torres Strait Islander status. After screening
about 180,000 households in non-community areas,
approximately 2.1% were identified. [Note, these
figures apply for all of Australia, not just NSW.]
Average 2.7 (excluding pneumococcal and influenza)
Within selected dwellings in community areas, up to
one Aboriginal and Torres Strait Islander adult (18
years of age or more) and up to one Aboriginal and
Torres Strait Islander child (0 to 17 years of age)
were randomly selected to participate in the survey.
[As above, this is not applicable to NSW as there
was no community sample].
Where a dwelling in a non-community area
contained one or more Aboriginal and Torres Strait
Islander usual residents, up to two Aboriginal and
Torres Strait Islander adults (18 years of age or
more) and up to two Aboriginal and Torres Strait
Islander children (0 to 17 years of age) were
randomly selected to participate in the survey.
Sample
56,677 respondents participated in the
NSW Population Health Survey, of whom
1,034 were Aboriginal and Torres Strait
Islander (approximately 1.8 per cent). Of
these, 930 were adults aged 16 years and
over.
Participation
rate
Participation rate was approximately 60%in
the overall survey. Not possible to calculate
a participation rate for Aboriginal and
Torres Strait Islander people only.
Households were contacted using list
assisted random digit dialling using
computer assisted telephone interviewing
(CATI). Up to 7 calls are made to establish
initial contact with a household and up to 5
calls are made to contact a selected
respondent. Carers or parents of children
aged 0–15 years were interviewed on their
behalf, not other proxy interviews were
allowed.
Collection
method
Weighting
Overall sample weighted to adjust for
differences in the probabilities of selection
among subjects and to adjust for
differences between the age and sex
structure of the sample and the Australian
Bureau of Statistics mid-year estimates for
NSW, excluding those living in non-private
dwellings. Further adjusted to the
Aboriginal and Torres Strait Islander
population of NSW as at December 2004.
A total of 10,044 Aboriginal and Torres Strait
Islander adults and children from across Australia
were surveyed in the NATSIHS. In addition, 395
Aboriginal and Torres Strait Islander Australians
were enumerated in the 2004-05 NHS sample of
25,906 persons. Thus the national sample consisted
of 10,439 Aboriginal and Torres Strait Islander
Australians of which 936 were in NSW and aged 16
years and over.
Approximately 83% of in-scope households
participated in non-remote areas.
Face to face interviews were conducted using a
Computer Assisted Interviewing (CAI) questionnaire.
The substance use questions however were paper
based and self-enumerated. Persons aged 18 years
or more were interviewed personally, with the
exception of persons who were too sick or otherwise
unable to respond personally. Persons aged 15 to 17
years were interviewed with the consent of a parent
or guardian. If consent wasn't obtained a parent or
guardian was interviewed on their behalf. For
persons aged less than 15 years, information was
obtained from a person responsible for the child.
Weighted for the probability of selection of the
household and then weighted to the estimated
resident Aboriginal and Torres Strait Islander
population of Australia as at 31 December 2004,
excluding those living in non-private dwellings.
Table 3 - Comparable demographic information for persons 16 years and over, from the 2002-2005
NSWPHS and the 2004-05 NSW-NATSIHS with the NSW Aboriginal and Torres Strait Islander population
from the 2001 Census
Demographic
NSWPHS
NSW-NATSIHS
NSW Aboriginal
(2002-2005)
(2004-05)
and Torres Strait
Islander 2001
Sample Weighted Sample Weighted
Population
sample
sample
38.7%
47.2%
43.4%
48.0%
48.5%
61.3%
52.8%
56.6%
52.0%
51.5%
Sex
Male
Female
Age
16-24
25-34
15.3%
18.5%
32.1%
22.5%
23.8%
22.2%
28.1%
23.3%
26.6%
25.5%
35-44
19.6%
19.7%
23.5%
21.1%
21.5%
45-54
19.7%
14.2%
16.3%
14.7%
14.1%
55-64
15.3%
7.4%
9.8%
9.0%
7.4%
65 years and over
11.6%
4.1%
4.4%
3.8%
4.9%
Income less than
$20,000
$20,000-$40,000
41.4%
31.9%
38.0%
35.5%
30.9%
24.9%
25.7%
30.5%
26.6%
32.3%
$40,000-$60,000
13.7%
16.4%
14.9%
17.0%
17.6%
$60,000 - $80,000
8.5%
9.5%
8.5%
10.8%
9.1%
Over $80,000
11.5%
16.5%
8.1%
10.1%
10.1%
Paying rent
Paying off dwelling
Fully owned
48.0%
19.7%
24.7%
51.7%
25.2%
18.9%
70.3%
17.8%
10.0%
65.0%
21.4%
11.5%
60.2%
20.4%
16.5%
7.6%
4.2%
n/a
n/a
2.9%
27.6%
22.2%
32.8%
13.2%
4.2%
50.3%
22.9%
21.7%
4.3%
0.8%
32.4%
30.0%
18.4%
13.7%
5.5%
41.9%
33.8%
19.4%
3.3%
1.6%
42.1%
32.4%
19.2%
4.6%
1.7%
Income*
Housing
arrangement**
Rent free tenure
AccessibilityMajor Cities
Remoteness Index Inner Regional
of Australia Plus Outer Regional
(ARIA+) ***
Remote
Very Remote
*In the NATSIHS, households whose income was not stated, not known, refused to answer or had no income,
were included in <$20,000 category.
**In the NATSIHS paying off dwelling includes shared equity scheme; and proportions have been calculated at
the Person Level using the total NSW 16+ population as the denominator.
***Accessibility-Remoteness Index of Australia Plus (ARIA+) based on the Australian Standard Geographical
Classification (ASGC).
Table 4: Prevalence estimates and statistical comparisons of comparable indicators, 2002–2005 NSW
Population Health Survey and 2004-05 National Aboriginal and Torres Strait Islander Health Survey
Indicators
Survey
Alcohol
(non-drinkers - 18
years and over)
2002-2005 NSWPHS
LCI% UCI SE RSE diff SE
z
p%
diff
value
27.1 23.4 31.0 1.9 7.2 7.70 3.08 2.50
0.01
2004-05 NSW-NATSIHS
19.4 14.7 24.1
2.4 12.3
Recommended fruit 2002-2005 NSWPHS
consumption
2004-05 NSW-NATSIHS
37.8 33.3 42.2
2.3
6.1 3.30 3.75 0.88
41.1 35.3 46.9
3.0
7.2
Recommended
vegetables
consumption
%
2002-2005 NSWPHS
9.5
6.9 12.0
1.3 14.0 1.00 1.84 0.54
2004-05 NSW-NATSIHS
8.5
6.0 11.0
1.3 15.1
Current smoking (18 2002-2005 NSWPHS
years and over)
2004-05 NSW-NATSIHS
44.6 39.9 49.3
2.4
5.4 8.30 3.89 2.13
52.9 46.9 58.9
3.1
5.8
Influenza
2002-2005 NSWPHS
vaccination
(50 years and over) 2004-05 NSW-NATSIHS
47.3 40.0 54.7
3.7
7.9 1.40 10.91 0.13
Pneumococcal
2002-2005 NSWPHS
vaccination
(50 years and over) 2004-05 NSW-NATSIHS
23.4 17.8 29.1
2.9 12.2 1.50 6.62 0.23
21.9 10.2 33.6
6.0 27.3
Positive self-rated
health
2002-2005 NSWPHS
77.3 73.6 81.0
1.9
2.4 1.20 3.09 0.39
2004-05 NSW-NATSIHS
76.1 71.3 80.9
2.4
3.2
Current asthma
2002-2005 NSWPHS
17.3 13.6 21.0
1.9 10.9 0.40 2.56 0.16
2004-05 NSW-NATSIHS
17.7 14.3 21.1
1.7
Diabetes
Overweight or
obese
0.19
0.29
0.02
0.45
48.7 28.6 68.8 10.3 21.1
0.35
0.44
9.8
2002-2005 NSWPHS
9.4
7.2 11.7
1.1 11.9 1.10 1.59 0.69
2004-05 NSW-NATSIHS
8.3
6.1 10.5
1.1 13.7
2002-2005 NSWPHS
48.8 43.9 53.6
2.5
5.1 1.50 3.61 0.42
2004-05 NSW-NATSIHS
50.3 45.2 55.4
2.6
5.2
Note: SE = Standard error; RSE = Relative standard error
0.41
0.24
0.34
Figure 1: Prevalence estimates of comparable indicators with 95% confidence intervals of comparable
indicators, 2002–2005 NSW Population Health Survey and 2004-05 National Aboriginal and Torres Strait
Islander Health Survey
Alcohol non-drinkers - 18 years and over
Recommended fruit intake
Recommended vegetable intake
Current smoking (18 years and over)
Influenza vaccination in last 12 months
Pneumococcal vaccination in last 5 years
Positive self rated health
Current Asthma
Diabetes
Overweight and obese
0
20
40
60
80
100
Percentage
2002-2005 NSWPHS
2004-05 NSW-NATSIHS